This proposal investigates using a battery of psychomotor and sensory tests for periodically monitoring industrial workers for subtle functional deficits associated with carpal tunnel syndrome (CTS). Although these tests are not intended for diagnosis, they should be sufficiently sensitive to detect early CTS deficits, yet be more specific for CTS than other monitoring instruments, such as self-reported or structured symptom surveys. Since these tests are automated and non-invasive, they may be suitable for routinely monitoring workers for early CTS, analogous to how audiometric tests are used for monitoring workers exposed to loud acoustic noise. Monitoring instruments are needed for active surveillance, for early detection of CTS before these cases progress into costly and disabling occupational illnesses, and for triggering ergonomics interventions. The Principal Investigator has already developed the biomedical instrumentation for this proposal. The tests were demonstrated to be reliable and sensitive for detection of psychomotor and sensory deficits associated with CTS. These tests were correlated with median nerve electrophysiologic parameters in a case-control study involving outpatients with electrophysiologically confirmed CTS, and a control group free of symptoms and electrodiagnostic parameters consistent with CTS. The proposal advances that work by proposing a prospective study for investigating if temporal changes in these test parameters can be observed among workers developing CTS symptoms. An industrial population of 250 workers exposed to risk factors associated with CTS from a variety of industries associated with high CTS incidence rates will be periodically tested for changes in psychomotor and sensory functional test parameters over a four year period. Workers will annually undergo examination for CTS, including electrophysiologic testing. Outcomes having positive/negative functional changes and positive/negative self reported symptoms will be ascertained and sensitivity, specificity and predictive value will be compared. In addition to these field investigations, new parameters for these instruments will be investigated using outpatient subjects and controls.